Torque-measuring wrench



Sept. 16, 1941. w. c. KRESS TORQUE-MEASURING WRENCH Filed Sept. 30, 11139 INVENTOR WM 0- W644,

Patented Sept. 16,1941

2,255,792 I TORQUE-MEASURING WRENCH Willard G. Kress, Kenmore, N. Y., assignor to J. B. Williams a 00., Buffalo, N. Y., a corporation of New York Application September so, 1929, Serial No. 291,225

3 Claims.

My present invention relates to a torque-measuring or indicating wrench and aims to provide certain improvements therein. More especially it constitutes an improvement upon the wrench construction disclosed in my Patent 'No. 2,167,- 720, dated August 1, 1939. I

Torque-indicating or measuring wrenches have been heretofore proposed for indicating the applied force in tightening cap-screws, bolts, nuts, and the like, and have recently found particular favor in the tightening of cap-screws or studs for holding down the heads of engine cylinders, the studs of which, if tightened unequally, cause distortion in the cylinder block and give rise to motor failure. In fact, many failures in motor rebuilding and cylinder block reboring jobs have been definitely traced to the unequal tightening of the cylinder head studs.

The torque-indicating and measuring wrenches heretofore proposed are of two general types: (1) those using springs or fluid pressure means for resisting and measuring the torque applied to the element being rotated; and (2) .those dependent upon the deflective torque on the shank or operating handle of the wrench, the deflection of which is indicated by a dial gauge or a member provided with a scale carried by the operating handle. Both types of the wrenches above described are open to certain objections. Those dependent upon the use of springs and fluid pressure means are usually complicated in construction or cumbersome and unwieldy in use. Those dependent upon the deflective torque of the operating handle have heretofore required either a dial gauge, which adds materially to the cost of the wrench and are subject to damage through rough use, while those dependent upon a scale which is affixed to the handle have had such scale element extending transversely of the handle, thereby rendering the wrench unsightly in appearance, clumsy to handle, and inconvenient for placing in containers or tool chests.

According to my present invention I have overcome the above recited objections by providing a torque-indicating wrench with a scale member which is preferably pivotally mounted on a wrench part in a manner such that when the wrench is not in use the scale member may be disposed in parallel relation to the handle,

handle and index whereby to provide for a large amount of deflection without interference with the wrench operation in close quarters. The invention will be better understood from the detailed description which follows when considered in conjunction with the accompanying drawing,

wherein:

Figure l is a top plan view of a torque-indicatm ing wrench embodying the novel features of my present invention, and showing the scale member in "on operative position.

Fig. 2 is a side elevation of the wrench shown in Fig. 1. I

Fig. 3 is a'section on. an-enlarged scale taken along the plane of the line 33 of Fig. '1.

Fig. 4 is a fractional top plan view showing the scale member in its off operative position.

Fig. 5 is a bottom plan view of the scale member. 1

Referring to the drawing, the numeral l0 indicates a shank or operating handle which has fixedly connected to one end thereof a driving head I l, which on its underside is provided with a square stud I! having a spring-pressed ball or other conventional means i3 for engaging in and driving a detachable socket (not shown) which is adapted to engage the head of a capscrew, a bolt, or a nut, for rotating the same. The opposite end of-the operating handle has aflixed thereto in any suitable manner a hand gribping portion l4 which may be suitably shaped to permit an eflicient grip thereon. As herein shown, the operating handle is attached to the hand-gripping portion by extending through an axial bore therein and being locked thereto by an anchoring rivet or the like [5.

The hand-gripping portion it at its inner end is formed with a plane to face l6 and an undercut groove or recess l8 providing a pair of side walls i1. Pivotally mounted on the top'plane face l6 by means of a rivet or the like I9 is a scale member 20 of flat, substantially elliptical form ,having along its longitudinal edges suitable inout of danger to accidental damage, in which dicia 2| which may be calibrated in any arbitrary units, such as foot pounds or the like. The pivotal connection of the scale member ,is adjacent one end thereof and preferably at a point concentric with the adjacent arcuate end of said member. The hand-gripping portion I4 is formed with a lug 22 which constitutes a stop forlimiting the pivotal rotation of said scale member in either a clockwise ,or a counterclockwise direction when it is desired to move said scale member into operative position, in which it extends transversely to the operating handle and preferably forms substantially a right angle therewith. For holding the scale member in its operative relations as shown in' Figs. 1 and 4, the underside of said scale member is formed with a socket or recess 23 at a point along the major axis of the ellipse, which socket is intended for cooperation with either one of two latching devices, each comprising a ball 24 mountedin a socket 25 in a side wall I! and urged outwardly by a helical spring 28. It desired, the underside of the scale member 2li may also be formed with additional sockets 21 for engagement with the spring-pressed balls 21 when said scale member occupies its inoperative position parallel to the operating handle.

Fixedly connected to the driving head II and extending in spaced, substantially parallel relation to the operating handle is a rigid rod or member 28, the free end of which is undercut as indicated at 29 and brought to a sharp point 30 in overlying relation to the scale member and constituting an index therefor. To the member 28 has been ascribed the term "cats whisker.

The length of the undercut portion of the cats whisker is such as to permit the scale member to be positioned or interposed in the space thus provided between the end of the cat's whisker and the operating handle I0 when it is desired to place the scale member in inoperative position. When the scale member 20 is so disposed, that is, as indicated in the dot and dash line in Figs. 1 and 4, it will be noted that it extends longitudinally of the operating handle and does not provide any projection or protruding means which may be damaged through the careless handling of the wrench when not in use. When the scale member is disposed in inoperative position as stated in the preceding sentence it will be apparent that the wrench may be readily put away into a container or tool chest without danger of damage to the wrench;

In the use of the wrench above described, the stud l2 will engage within and hold a socket member (not shown) in assembled relation on the driving head in a manner well known, and upon engaging such socket with the head of a capscrew, a bolt, a-nut or the like, it will be apparent that by gripping the hand-gripping portion I 4 and moving it through an arc in a clockwise direction with the axis of the socket head as a fulcrum, the cap-screw, bolt or nut will be rotated and thereby fastened onto its comp1e-- mentary part. For determining the amount of force with which such cap-screw, bolt, or nut is being tightened, the scale member is moved to its "on position as shown in Fig. 1, and as the rotatable element is brought up into tightenedrelation with its cooperating part it will be apparent that the operatinghandle l0 will flex or be de- 1 flected under the applied force of tightening the rotatable element, which applied force will be indicated by the movement of the scale member 2| which will ride under the index 30 of the stationary cats whisker 28. Where it is'desired to determine the force necessary to loosen a cap-screw, bolt, nut, or the like, or where the force is applied. to a left hand threaded member of said ing such applied force the index member 26 will be moved to the position shown in Fig. 4. By having the scale member extend at substantially a right angle to the index element it will be appreciated that a means is provided whereby a relatively small deflection in the operating handle will be quite pronounced on the scale member thereby facilitating the accurate reading of the deflection. It will also be noted that because of the adjustability of the scale member to either the "on" or "ofl' and 4, respectively, terfere with the wrench operation in close quarters since movement or flexing of the operating handle will be in a-direction opposite to that in which the scale member extends.

The wrench will be capable of giving an infinite number of accurate readings of deflective torque so long as the handle is not stressed beyond the elastic limit of the stock from which it is made. It will thus be apparent that I have provided an exceedingly simple torque-indicating wrench which is especially useful for the purposes set forth, and while I have shown and described but a single embodiment of my invention, I do not wish to be limited to the specific details of construction disclosed since it will be apparent to those skilled in the art that changes may be made therein without departing from the spirit of the invention.

What I claim is:

parts, one being an operating handle capable of I flexing under operating load and having driving means'at one end for engaging and rotating a rotatable element, and the other part being a member extending in spaced substantially parallel relation to the handle, one end of said member being fixedly connected to the driving-means and the other end of said member being free, and cooperating means on the free end of said member and on the handle for indicating the deflective torque on the handle when applying turning force through said handle to a rotatable element, said cooperating means comprising an index on one of the parts and a scale element pivotally mounted at one end on the other of said parts between said parts, said scale ele-' and movable ment being adapted to be moved to either of two operative positions of the opposite sides of the handle to extend transversely to the parts and in inoperative position to extend longitudinally of the parts, and means for selectively holding the scale element in either of said positions.

2. A torque indicating wrench according to claim 1, wherein the scale element is pivotally mounted on the handle.

3. A torque indicating wrench according to claim 1, wherein the means for selectively holding the scale element in either of its positions consists of cooperating latching means on the scale element and on the part by which it is carried.

' WILLARD C. KRESS.

position as shown in Figs. 1- the scale member will not in- 

